A dual extrusion printer, as you've probably guessed, has two extruders. This means you can run two filaments through the same print without having to pause the print and change the filament. Consider these dice -- since the printer lays down plastic in .2mm layers, if I wanted to print the dice with a single extruder printer I'd have to pause on almost every single layer, change the filament, and resume printing.

Personalized dice for a Reddit Gifts match.

Keep in mind that a filament change means moving the extruder head away from the print, heating it up to 240 C, feeding the new filament while flushing the own, then lowering the temperature back to ~180 C before resuming the print. That's a lot of time, a lot of unnecessary heating and cooling of the extruder nozzles, and a lot of wasted filament.

That's 75 filament changes. Yikes. There are a couple of ways you can minimize that pain or get around it. First, if you had a bunch of dice to print you could produce ten or twenty at once; that would get you more print time for every filament swap. (But still, 75 filament changes!) You could also leave the pips or numbers as voids, either painting them in after printing or using a 3D pen to fill in the blanks.

I do enough multi-filament printing that I'd much rather just have the dual extruder printer, of course. And, as I'll show in a future blog, the dual extruder also provides solutions for some tricky printing scenarios.